Colon, Rectum, Anus Flashcards
(121 cards)
1
Q
Parts of the Large Intestine
A
Cecum, appendix, colon (A, T, D, S), Rectum, Anus
2
Q
Movement of the colon
A
Gastrocolic reflex
3
Q
What gives you the urge to defecate?
A
Stretching or distention (stimulus) of the segments of the rectum
4
Q
An exaggerated gastrocolic response wherein a person defecates right after eating
A
irritable bowel syndrome
5
Q
The act of expelling wastes from the digestive tract
A
Defecation
6
Q
the gas from stool due to what?
A
flatus due to sulfur containing compounds
7
Q
Derivatives of the foregut
A
stomach to middle duodenum, liver, pancreas, spleen
8
Q
derivatives of the midgut
A
middle duodenum to left colic flexure
9
Q
derivatives of the hindgut
A
left colic flexure to rectum
10
Q
axis during gut rotation and vascularization: foregut
A
celiac trunk
11
Q
axis during gut rotation and vascularization: midgut
A
superior mesenteric artery
12
Q
axis during gut rotation and vascularization: hindgut
A
inferior mesenteric artery
13
Q
Pain localization: foregut
A
epigastric
14
Q
pain localization: midgut
A
periumbilical region
15
Q
pain localization: hindgut
A
hypogastric region
16
Q
T/F Large intestine is about 1/5 the length of the SI
A
True. it is around 5 feet long
17
Q
How many liters of chyme enter the cecum each day
A
1L
18
Q
how much chyme is excreted in the feces?
A
100cc about 1/10 water
19
Q
is the semi-liquid acid mass formed when food passes from the stomach to the small intestine
A
chyme
20
Q
Absorption of water and electrolytes happen where and what are its parts
A
right colon: from ascending colon to midpoint of transverse
21
Q
Propulsion and storage of unabsorbed fecal water for evacuation and what are its parts
A
Left colon: from midpt of transverse colon to the sigmoid colon
22
Q
Right colon is derived from
A
midgut
23
Q
left colon is derived from
A
hindgut
24
Q
right colon has a _____ wall than left colon
A
thinner
25
Right colon has _____ lumen than left colon
Larger
26
Right colon has more or less fluid than left colon?
More
27
Thickened bands of smooth muscle
Teaniae coli
28
Longitudinal layer of the colon
teaniae coli
29
Teaniae coli: complete or incomplete
complete
30
Three bands of the teaniae coli
mesocolic: transverse and sigmoid
omental: appendices epiploicae
free: no attachment
31
outpouchings of the colon
haustra
32
in between teaniae coli
haustra
33
why are haustra formed?
teaniae coli are shorter than the intestines
34
Distinguish the colon from the small intestine in an xray or endoscope
plicae circulares (reaches the whole circumference of the SI) unlike haustrae
35
small fatty like omentum-like projectiuons distributed near the area of teaniae coli along the wall of colon
epiploic appendages
36
Functions of epiploic appendages
protect and cushion the colon
blood depository during colonic vessel contraction
fat storage role in absorption and immune response
seal perforations
37
cecum is located where
RLQ
38
widest part of the colon
cecum
39
blind intestinal pouch
cecum
40
has no mesentery but almost all covered by peritoneum
cecum
41
two openings of the cecum
ileocecal valve
| opening of the appendix
42
not a real valve but prevents reflex of contents into the ileum
ileocecal valve
43
Gut associated lymphoid tissue (GALT) in the embryo but turns vestigial
appendix
44
location of appendix
RLQ
45
blind intestinal diverticulum that contains masses of lymphoid tissue
appendix
46
appendix is suspended by
mesoappendix
47
Most common surgical emergency
appendectomy
48
Good morning appendix
appendix that just pops out upon opening the peritoneum
49
Cute appendix
appendix is normal but should still be removed
50
Position of the appendix
retrocecal 64% of the time
retroileal
pelvic
51
location of appendix via a diagonal incision
McBurney's point
52
McBurney's point
1/3 of the way along oblique line joining the right ASIS to the umbilicus
53
now, how to find appendix?
pt of maximal tenderness
54
Vasculature of cecum
ileocolic artery (terminal branch of SMA)
55
vasculature of appendix
appendicular artery
56
causes of appendicitis
obstruction of the lumen of the appendix -> intraluminal pressure -> venous congestion -> inflammation
57
Referred pain of appendicitis
initially starts inRUQ or in epigastric region then localizes to RLQ
58
Natural reflex of pain
guarding behavior and abdominal rigidity
59
Diagnostics of appendicitis
```
Psoas sign (hip extension)
Obturator sign (hip flexion and internal rotation, coughing)
Rovsing's sign (pain in RLQ when pressure is applied in LLQ)
Rebound ternderness (more pain felt when pressure in released in RLQ)
```
60
2nd part of the intestine
ascending colon
61
ascending colon is intraperitoneal T/F
False. It is retroperitoneal
62
T/F ascending colon has no mesentery
True but peritoneum covers anterior and lateral with areolar tissue posteriorly
63
Longest and most mobile part of the colon
transverse
64
T/F transverse is completely covered by the peritoneum
True.
65
transverse colon: intra or retroperi
Intraperitoneal
66
Mesentery of the transverse colon
transverse mesocolon
67
Serves as the natural barrier for reciprocal infection
Transverse Mesocolon
68
Arterial anastomosis: transverse colon
marginal artery of Drummond
69
T/F IMA and SMA can be cut and bowels will still survive
True but SMA supplies the intestine and SI will not survive
70
descending colon: intra or retroperi
retro
71
Mainly immobile part of the colon
descending, no mesentery
72
Sigmoid colon: intra or retroperi
Intraperitoneal
73
Most prone part of colon to twisting
sigmoid colon
74
site at which the sigmoid colon becomes the rectum
rectosigmoid junction
75
Rectosigmoid jxn: with peritoneum?
No peritoneym, true mesentery
76
Where does the 3 taeniae coli converge?
Sigmoid colon
77
Twisting of the colon on itself or on the mesenteric tissue causing obstruction
Volvulus
78
one section of the bowel tunnels into an adjoining section
small bowel and colonic intussusception
79
cecum goes inside the ascending colon
colocolic intussusceptions
80
```
The anastomosis of
ileocolic
right colic
middle colic
left colic
sigmoidal arteries
around the internal margin of the cecum and colon
```
Marginal artery of Drummond
81
connects IMA to middle colic
Meandering Mesenteric Artery (Arc of Rolan)
82
Arterial arcade in colon
between ascending and descending colon
83
imptance of the arcade in the colon
colon will survive even if a section of the colon is removed
84
Venous supply of colon
follow arteries except IMV (more superior)
goes to portal circulation! not systemic
85
Suspensory ligament that connects the duodenum to the diaphragm
Ligament of Treitz
86
T/F colon will have both sytematic and portal circulation
True
87
Lymphatic Drainage of Intestines
entire colon and proximal 2/3 of the rectum: paraaortic LN to cisterna chylii
remaining rectum and anus: same or drain to the internal iliac and superficial inguinal nodes
88
Innervation of the large intestine
Sympathetic:
SM plexus, IM plexus and the hypogastric plexus inhibit colonic motility
Parasympathetic:
Vagus nerve, sacral nerve, preganlionic fibers (motility)
Colonic wall intrinsic plexus:
aka myenteric/auerbach's/submucous/meissner's (major control of motility)
89
Anatomically starts at the S3 vertebral body
Rectum
90
Surgically starts at the sacral promontory
Rectum
91
Perforation in which region of the rectum will be safer?
Posterior region because material can be drained extraperitoneally. Anterior region will cause fecal matter to enter peritoneum
92
Rectum is intra or retroperitoneal?
EXTRAperitoneal with fascia propria
93
Sphincters of the rectum
Internal - superior 2/3 of rectum
| External - inferior 1/3
94
Internal sphincter is controlled by
autonomic nervous system
95
The 3 U shaped loops of the external sphincter
puborectalis - top loop/ deep
superficial anal sphincter - intermediate loop
subcutaneous portion - base loop
96
External sphincter controlled by
pudendal nerve (somatic innervation)
97
Arterial supply of the rectum
superior rectal
middle and inferior rectal
middle sacral
98
Venous drainage of the rectum
superior rectal vein
| inferior rectal vein
99
3 lateral curves of the rectum
Valves of Houston
100
point of anterior peritoneal reflection
middle rectal valve (valves of houston)
101
dilated terminal portion of the rectum?
| significance?
ampulla of the rectum
| neonates are ale to hold their fecal matter up to two weeks
102
Fasciae of the rectum
Presacral (waldeyer's) fascia
Rectovesical: denonvillier's fascia (males)
lateral ligament: middle rectal vessels
Rectal fascia proper: rectum n mesorectum
103
surrounds posterior 1/2 or more of the rectum, enveloped by thin fibrous covering(which is?)
Mesorectum
| Fascia Propria
104
important oncologic barrier to primary and lymphatic spread to extrarectal pelvic tissues
mesorectum
105
Anatomically from dentate line to anal verge
Anus
106
Surgically: terminal protion of large bowel that passes through levator ani and opens to the anal verge 4cm in length
anus
107
Formed via teh anteriorly directed pull of the purorectalis muscle; usually acute
Anorectal angle
108
anorectal angle
mean angle: 102 degrees
sitting: 119
sphincter squeeze: 81
109
flap valve effect
puborectalis pulls rectum anteriorly during squeeze, increasing intraabdominal pressure
110
most important element to maintain fecal continence
puborectalis muscle
111
Venous drainage of anus
via portal and systemic circulation
112
Nerve supply to anorectal region
Somatic innervation: (PuInPer)
pudendal nerve
inferior rectal n: sensory and motor
perineal n: sensory and motor to perineal region
Autonomic innervation:
sympathetics from thoracolumbar via hypogastric plexus and nerve
Parasympathetic from S2-S4
113
Rectal cancer operation may lead to what ?
dennervation in pelvic area, bladder dysfunction, sexual dysfunction
114
When these are occluded, secondary infection may occur
Columns of Morgagni
115
between the columns of morgagni are
anal glands
116
differentiates external from internal hemorrhoids
pectinate line
above: internal
below: external
117
3 consistently placed submucosal vascular plexuses formed by anastomosis of rectal veins within anal canals
anal cushions
118
Differentiate internal and external hemorrhoids
internal painless and drain to portal circ.
| external painful and drain to IVC
119
I-IV Grading o fPiles
Grade
1: hardly seen
2: bulgen then disappears
3: visible bulges can be pushed inside
4: cannot be pushed inside
120
types of hemorrhoids
Internal, external, mixed
121
usual position of internal hemorrhoids
left lateral, right anterior, right posterior
